WALTHAM -- Officials remain silent about a 34-year-old Waltham man who died last week, but the man who identified himself as the victim's boyfriend says three juveniles have been arrested in connection with the death.

Emmanuel Dolin last talked to Thierry Tullus on Aug. 18 at about 4:30 p.m. The conversation happened two days before Tullus' body was found at 148 Overland Road in the back seat of his own car with his leg hanging out the door.

Dolin, who says he and Tullus have dated since January 2013, said nothing was unusual about their last conversation. Dolin said Tullus told him he would call later, but he didn't.

"I spoke with a detective working on the case and he mentioned that there were people in custody who definitely have something to do with the death. I also know he was beat up," Dolin said. "They don't release any information about [the suspects] because they're juvenile."

The Middlesex District Attorney's Office, tasked with disseminating information, confirmed a death on Overland Road last Wednesday, but wouldn't release the name of the deceased. A spokeswoman said they won't release any more information about the death until they receive a toxicology report, which could take weeks.

The spokeswoman wouldn't confirm or deny whether anyone had been arrested in connection with the death, but courthouse officials were instructed to bring three juveniles up to the courtroom through the back entrance last Friday.

The Waltham Police Department has referred all questions to the DA's office.

Tullus' family last week confirmed it was his body police found on Overland Road. Police taped off a portion of the mostly residential road running parallel to Main Street. They investigated the scene and dusted for prints from about 3 p.m. until the body was removed after 9 p.m., neighbors said.

Dolin said he knew something was awry when Tullus didn't call him Tuesday morning. A daily wakeup call was customary in their relationship, Dolin said.

"He's not [home], he's not picking up his phone and I know Thierry is missing," Dolin said.

Last week, Tullus' relatives said they last saw him Monday evening, before he left the house to go out.

"People are crying in the house and it's just terrible," his sister Laurie Pierre said last week.

Dolin said he started looking everywhere Tuesday, searching any place Tullus might go.

"On Wednesday I said, ‘this is the last day for me to find Thierry. If I don't find him today – it's a different story,'" Dolin said.

He added that since last week, he hasn't been told anything more about Tullus' death, putting him in a state of despair.

"There are so many questions that I will never find answers to," Dolin said.